- The risk for becoming addicted to drugs varies among individual, even those using similar drugs in a similar way. It is not known why some people become addicted and others do not. Studies suggest that some genes may increase the risk of addiction. Negative life experiences may also affect the risk of addiction. Researchers want to test smokers and nonsmokers to study genetic and brain function traits that may lead to drug addiction.

Objectives:

- To understand brain function in people who may be at a higher risk of drug addiction.

Eligibility:

Healthy volunteers between 18 and 55 years of age.

Smokers (10 to 30 cigarettes per day for more than 2 years) and nonsmokers will be eligible.

Design:

Participants will be screened with a physical exam and medical history. They will be tested for drug and alcohol use. A blood sample will be collected.

The study will involve one visit. Participants will have a magnetic resonance imaging (MRI) scan.

At the visit, participants will answer questions about their health and drug use habits. They will then be trained on the tasks they will do during the MRI scan. After the training, they will have the scan and perform the tasks. The scan and tasks will look at brain function related to rewards and impulsiveness.

Other computer tests will be given after the scan. These tests will measure learning, memory, and impulsiveness.

Further study details as provided by National Institutes of Health Clinical Center (CC):

Primary Outcome Measures:

The primary outcome measures will be BOLD fMRI activation and behavioral performance on various cognitive tasks that deal with impulse control and reward learning, as a function of gene x environment interactions.

Estimated Enrollment:

120

Study Start Date:

June 2012

Detailed Description:

Background: Even under similar drug use patterns, the risk for drug addiction varies from individual to individual. However, the neurobiological mechanisms underlying this variability are poorly understood and characterized. Studies suggest that certain traits observed in substance dependent individuals may actually precede drug use, and could augur future substance dependence. Understanding how the presence of these traits increases vulnerability to substance addiction could aid in the development of early intervention, preventative measures, as well as better treatment strategies.

Objective: The primary goal of this protocol is to improve our understanding of increased susceptibility to developing substance addiction. We focus here on particular gene x environment interactions as increased risk factors for substance dependence. The emphasis is on monoaminergic neurotransmitter-related genes thought to influence adaptability to the environment, and, therefore, on cognitive domains related to dopamine and serotonin: reward and punishment learning, and impulse control. To achieve the above objective, the study will be implemented by using cognitive, genetic and neuroimaging testing in adult addicted individuals along with matched controls.

Outcome Measures: The primary outcome measures will be BOLD fMRI activation and behavioral performance on various cognitive tasks that deal with impulse control and reward learning, as a function of gene x environment interactions.

History of psychosis or any current DSM-IV axis I disorder (other than simple phobia);

Current use of psychotropic medication that may alter attentional functioning (e.g., Clonidine, antipsychotics, Venlafaxine, stimulants);

Current use of substances on the study visit that might influence performance on tasks as assessed by self-report, carbon monoxide (CO) monitoring, alcohol breathalyzer and urine testing; (and neuromotor evaluation, when needed). If participant is intoxicated at the time of the study visit; he/she will be rescheduled for a later visit.

Meets criteria for abuse, or DSM-IV dependence, or dependence in partial remission, on any drug except nicotine. Past abuse of marijuana or alcohol is acceptable provided it is at least 1 year in the past.

Pregnancy, which will be assessed by history during screening and by urine testing on scan days;

Claustrophobia by self report, or through response to the mock-scanner environment, severe enough to preclude toleration of the scanning environment.

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01621607